Sulfopyridones and a process of making therefor

ABSTRACT

Azo dyes of the formula ##STR1## where D is the radical of a diazo component, and 
     X is substituted or unsubstituted C 2  -C 8  -alkylene, 
     in the form of the free acid or its salts, the use thereof for dyeing or printing natural or synthetic substrates, sulfopyridones as coupling components for these dyes, and a process for preparing them.

This is a Division of application Ser. No. 08/432,815 filed on May 2,1995, now U.S. Pat. No. 5,554,737.

The present invention relates to novel azo dyes of the formula I##STR2## where D is the radical of a diazo component, and

X is C₂ -C₈ -alkylene with or without interruption by an oxygen atom inether function,

in the form of the free acid or its salts, to the use thereof for dyeingor printing natural or synthetic substrates, to sulfopyridones ascoupling components for these dyes, and to a process for preparing them.

It is an object of the present invention to provide novel azo dyes whichhave doubled 3-hydroxysulfonyl-4-methyl-6-hydroxypyrid-2-ones ascoupling component and advantageous application properties.

We have found that this object is achieved by the above-defined azo dyesof the formula I.

The novel azo dyes of the formula I can be present either in the form ofthe free acid or else as salts.

Suitable salts are metal or ammonium salts. Metal salts include inparticular the lithium, sodium or potassium salts. Ammonium salts forthe purposes of the present invention are salts with subtituted orunsubstituted ammonium cations. Substituted ammonium cations include forexample monoalkyl-, dialkyl-, trialkyl-, tetraalkyl- orbenzyltrialkyl-ammonium cations or cations derived fromnitrogen-containing five- or six-membered saturated heterocycles, suchas pyrrolidinium, piperidinium, morpholinium, piperazinium orN-alkylpiperazinium cations or their N-monoalkyl- orN,N-dialkyl-substituted products. Alkyl for the purposes of the presentinvention is generally straight-chain or branched C₁ -C₂₀ -alkyl whichmay be substituted by hydroxyl groups and/or may be interrupted by from1 to 4 oxygen atoms in ether function.

Any alkyl or alkylene appearing in the abovementioned formula may bestraight-chain or branched.

X is for example CH₂, (CH₂)₂, (CH₂)₃, (CH₂)₄, (CH₂)₅, (CH₂)₆, (CH₂)₇,(CH₂)₈, CH(CH₃)CH₂, CH(CH₃)CH(CH₃), C₂ H₄ OC₂ H₄, C₃ H₆ OC₂ H₄, C₃ H₆OC₃ H₆, C₄ H₈ OC₃ H₆ or C₄ H₈ OC₄ H₈.

Of importance are azo dyes of the formula I where D is the radical of adiazo component derived from an aniline, from an aminonaphthalene orfrom a five-membered aromatic heterocyclic amine which contains from oneto three hetero atoms selected from the group consisting of nitrogen,oxygen and sulfur in the heterocyclic ring with or without a fused-onbenzene, thiophene, pyridine or pyrimidine ring.

Important azo dyes of the formula I are those where D is the radical ofa diazo component derived from an aniline, from an aminonaphthalene orfrom a heterocyclic amine of the pyrrole, furan, thiophene, pyrazole,imidazole, oxazole, isoxazole, thiazole, isothiazole, triazole,oxadiazole, thiadiazole, benzofuran, benzothiophene, benzimidazole,benzoxazole, benzothiazole, benzisothiazole, pyridothiophene,pyrimidothiophene, thienothiophene or thienothiazole series.

Of particular importance are azo dyes of the formula I where D is theradical of a diazo component derived from an aniline or from anaminonaphthalene, anilines being especially important.

Of industrial significance are azo dyes of the formula I where D is theradical of a diazo component derived from an aminobenzophenone, from anaminoazobenzene or from an aminobenzoic acid.

D radicals conform for example to the formula ##STR3## where L¹ isnitro, cyano, C₁ -C₆ -alkanoyl, benzoyl, C₁ -C₆ -alkylsulfonyl,substituted or unsubstituted phenylsulfonyl or a radical of the formula--CH═T, where T is hydroxyimino, C₁ -C₄ -alkoxyimino or a radical of anacidic CH compound,

L² is hydrogen, C₁ -C₆ -alkyl, halogen, hydroxyl, mercapto,unsubstituted or phenyl- or C₁ -C₄ -alkoxy-substituted C₁ -C₆ -alkoxy,substituted or unsubstituted phenoxy, unsubstituted orphenyl-substituted C₁ -C₆ -alkylthio, substituted or unsubstitutedphenylthio, C₁ -C₆ -alkylsulfonyl or substituted or unsubstitutedphenylsulfonyl,

L³ is cyano, C₁ -C₄ -alkoxycarbonyl, carboxyl or nitro,

L⁴ is hydrogen, C₁ -C₆ -alkyl or phenyl,

L⁵ is C₁ -C₆ -alkyl or phenyl,

L⁶ is hydrogen, cyano, C₁ -C₄ -alkoxycarbonyl, carboxyl, C₁ -C₆-alkanoyl, thiocyanato or halogen,

L⁷ is nitro, cyano, C₁ -C₆ -alkanoyl, benzoyl, C₁ -C₄ -alkoxycarbonyl,carboxyl, C₁ -C₆ -alkylsulfonyl, substituted or unsubstitutedphenylsulfonyl or a radical of the formula --CH═T, where T is as definedabove,

L⁸ is hydrogen, C₁ -C₆ -alkyl, cyano, halogen, unsubstituted or phenyl-or C₁ -C₄ -alkoxy-substituted C₁ -C₆ -alkoxy, unsubstituted orphenyl-substituted C₁ -C₆ -alkylthio, substituted or unsubstitutedphenylthio, C₁ -C₆ -alkylsulfonyl, substituted or unsubstitutedphenylsulfonyl, C₁ -C₄ -alkoxycarbonyl or carboxyl,

L⁹ is cyano, unsubstituted or phenyl-substituted C₁ -C₆ -alkyl,unsubstituted or phenyl-substituted C₁ -C₆ -alkylthio, substituted orunsubstituted phenyl, thienyl, C₁ -C₄ -alkylthienyl, pyridyl or C₁ -C₄-alkylpyridyl,

L¹⁰ is phenyl or pyridyl,

L¹¹ is trifluoromethyl, nitro, C₁ -C₆ -alkyl, phenyl, unsubstituted orphenyl-substituted C₁ -C₆ -alkylthio or di(C₁ -C₆ -alkyl)amino,

L¹² is C₁ -C₆ -alkyl, phenyl, 2-cyanoethylthio or 2-(C₁ -C₄-alkoxycarbonyl)ethylthio,

L¹³ is hydrogen, nitro or halogen,

L¹⁴ is hydrogen, cyano, C₁ -C₄ -alkoxycarbonyl, carboxyl, nitro orhalogen,

L¹⁵ and L¹⁶ are identical or different and each is independently of theother hydrogen, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy or halogen,

L¹⁷ is hydrogen, C₁ -C₆ -alkyl, trifluoromethyl, C₁ -C₆ -alkanoyl,substituted or unsubstituted benzoyl, C₁ -C₄ -alkoxycarbonyl,hydroxysulfonyl, substituted or unsubstituted phenylsulfonyloxy, mono-or di(C₁ -C₄ -alkyl)carbamoyl, mono- or di(C₁ -C₄)alkylsulfamoyl, C₁ -C₄-alkanoylamino, hydroxysulfonyl- or carboxylphenyl-azo, 5-(C₁ -C₄-alkyl)-1,2,4-oxadiazol-3-yl or6-hydroxysulfonyl-7-methylbenzothiazol-2-yl, and

the ring A may have a fused-on benzene or hydroxysulfonylbenzene ring.

Any alkyl or alkylene appearing in the abovementioned formulae may bestraight-chain or branched.

Any substituted phenyl appearing in the abovementioned formulae of theazo dyes may contain as substituents for example C₁ -C₄ -alkyl,chlorine, bromine, nitro or C₁ -C₄ -alkoxy. The number of substituentsin substituted phenyl is generally from 1 to 3.

The number of substituents in substituted alkyl is generally 1 or 2.

L², L⁴, L⁵, L⁸, L⁹, L¹¹, L¹², L¹⁵, L¹⁶ and L¹⁷ are each for examplemethyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl,isopentyl, neopentyl, tert-pentyl, hexyl or 2-methylpentyl.

L⁹ may also be for example benzyl or 1- or 2-phenylethyl.

L², L⁸, L⁹ and L¹¹ may each also be for example methylthio, ethylthio,propylthio, isopropylthio, butylthio, isobutylthio, pentylthio,hexylthio, benzylthio or 1- or 2-phenylethylthio.

L² and L⁸ may each also be for example phenylthio, 2-methylphenylthio,2-methoxyphenylthio or 2-chlorophenylthio.

L², L⁸, L¹⁵ and L¹⁶ may each also be for example methoxy, ethoxy,propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, pentyloxy,isopentyloxy, neopentyloxy, tert-pentyloxy, hexyloxy or2-methylpentyloxy.

L², L⁸, L¹³, L¹⁴, L¹⁵ and L¹⁶ may each also be for example fluorine,chlorine or bromine.

L⁷, as well as L¹, L² and L⁸, is for example methylsulfonyl,ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl,isobutylsulfonyl sec-butylsulfonyl, pentylsulfonyl, isopentylsulfonyl,neopentylsulfonyl, hexylsulfonyl, phenylsulfonyl,2-methylphenylsulfonyl, 2-methoxyphenylsulfonyl or2-chlorophenylsulfonyl.

L³, as well as L⁶, L⁷, L⁸, L¹⁴ and L¹⁷, is for example methoxycarbonyl,ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl,isobutoxycarbonyl or sec-butoxycarbonyl.

L² and L⁸ may each also be for example 2-methoxyethoxy, 2-ethoxyethoxy,2- or 3-methoxypropoxy, 2- or 3-ethoxypropoxy, 2- or 4-methoxybutoxy, 2-or 4-ethoxybutoxy, 5-methoxypentyloxy, 5-ethoxypentyloxy,6-methoxyhexyloxy, 6-ethoxyhexyloxy, benzyloxy or 1- or 2-phenylethoxy.

L¹¹ may also be for example dimethylamino, diethylamino, dipropylamino,diisopropylamino, dibutylamino, dipentylamino, dihexylamino orN-methyl-N-ethylamino.

L¹² may also be for example 2-methoxycarbonylethylthio or2-ethoxycarbonylethylthio.

L⁹ may also be for example phenyl, 2-, 3- or 4-methylphenyl,2,4-dimethylphenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-chlorophenyl,2-, 3- or 4-methoxyphenyl, 2- or 3-methylthienyl or 2-, 3- or4-methylpyridyl.

L¹, L⁶, L⁷ and L¹⁷ may each also be for example formyl, acetyl,propionyl, butyryl, pentanoyl or hexanoyl.

L¹⁷ may also be for example benzoyl, 2-, 3- or 4-methylbenzoyl, 2-, 3-or 4-ethylbenzoyl, 2-, 3- or 4-propylbenzoyl, 2-, 3- or4-isopropylbenzoyl, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-dimethylbenzoyl,2-methyl-4-methoxybenzoyl, 2-, 3- or 4-methoxybenzoyl, 2-, 3- or4-ethoxybenzoyl, phenylsulfonyloxy, 2-, 3- or 4-methylphenylsulfonyloxy,mono- or dimethylcarbamoyl, Mono- or diethylcarbamoyl, mono- ordipropylcarbamoyl, mono- or diisopropylcarbamoyl, mono- ordibutylcarbamoyl, mono- or dimethylsulfamoyl, mono- or diethylsulfamoyl,mono- or dipropylsulfamoyl, mono- or diisopropylsulfamoyl, mono- ordibutylsulfamoyl, formylamino, acetylamino, propionylamino,butyrylamino, isobutyrylamino, 4-hydroxysulfonylphenylazo,4-carboxylphenylazo, 5-methyl-1,2,4-oxadiazol-3-yl or5-ethyl-1,2,4-oxadiazol-3-yl.

When L¹ or L⁷ is the radical --CH═T where T is derived from an acidic CHcompound H₂ T, suitable acidic CH compounds H₂ T include for examplecompounds of the formula ##STR4## where Z¹ is cyano, nitro, C₁ -C₄-alkanoyl, substituted or unsubstituted benzoyl, C₁ -C₄ -alkylsulfonyl,substituted or unsubstituted phenylsulfonyl, carboxyl, C₁ -C₄-alkoxycarbonyl, C₃ -C₄ -alkenyloxycarbonyl, phenoxycarbonyl, carbamoyl,mono- or di(C₁ -C₄ -alkyl)carbamoyl, substituted or unsubstitutedphenylcarbamoyl, substituted or unsubstituted phenyl, benzothiazol-2-yl,benzimidazol-2-yl, 5-phenyl-1,3,4-thiadiazol-2-yl or2-hydroxychinoxalin-3-yl,

Z² is C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or C₃ -C₄ -alkenyloxy,

Z³ is C₁ -C₄ -alkoxycarbonyl, C₃ -C₄ -alkenyloxycarbonyl,phenylcarbamoyl or benzimidazol-2-yl,

Z⁴ is cyano, C₁ -C₄ -alkoxycarbonyl or C₃ -C₄ -alkenyloxycarbonyl,

Z⁵ is hydrogen or C₁ -C₆ -alkyl,

Z⁶ is hydrogen, C₁ -C₄ -Alkyl or phenyl and

Z⁷ is C₁ -C₄ -alkyl.

Attention is drawn to the radical derived from compounds of the formulaIIIa, IIIb or IIIc where Z¹ is cyano, C₁ -C₄ -alkanoyl, C₁ -C₄-alkoxycarbonyl or C₃ -C₄ -alkenyloxycarbonyl, Z² is C₁ -C₄ -alkyl, C₁-C₄ -alkoxy or C₃ -C₄ -alkenyloxy, Z³ is C₁ -C₄ -alkoxycarbonyl or C₃-C₄ -alkenyloxycarbonyl and Z⁴ is cyano.

Particular attention is drawn to the radical derived from compounds ofthe formula IIIa, IIIb or IIIc where Z¹ is cyano, C₁ -C₄ -alkoxycarbonylor C₃ -C₄ -alkenyloxycarbonyl, Z² is C₁ -C₄ -alkoxy or C₂ -C₄-alkenyloxy, Z³ is C₁ -C₄ -alkoxycarbonyl or C₃ -C₄ -alkenyloxycarbonyland Z⁴ is cyano.

Preference is given to azo dyes of the formula Ia ##STR5## where L¹⁵,L¹⁶, L¹⁷, X and the ring A are each as defined above.

Particular preference is given to azo dyes of the formula Ib ##STR6##where X is as defined above, L¹⁵ and L¹⁶ are each hydrogen and L¹⁷ issubstituted or unsubstituted benzoyl, or L¹⁵ and L¹⁶ are, independentlyof each other, hydrogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy and L¹⁷ ishydroxysulfonylphenylazo or carboxylphenylazo.

Particular preference is further given to azo dyes of the formula Ic##STR7## where one of Z¹ and Z² is hydrogen and the other is C₁ -C₄-alkoxycarbonyl and X is as defined above.

The azo dyes of the formula I according to the present invention can beobtained in a conventional manner, for example by diazotizing an amineof the formula IV

    D--NH.sub.2                                                (IV),

where D is as defined above, and coupling the resulting diazonium saltwith a sulfopyridone of the formula V ##STR8## where X is as definedabove.

The present invention further provides sulfopyridones of the formula V##STR9## where X is C₂ -C₈ -alkylene with or without interruption by anoxygen atom in ether function, in the form of the free acid or itssalts.

The invention also provides an advantageous process for preparing thesulfopyridones of the formula V, which comprises treating acyanopyridone of the formula VI ##STR10## where X is as defined above,in concentrated sulfuric acid at from 80° to 130° C.

Preferably the novel process is carried out at from 90° to 125° C.

Concentrated sulfuric acid for the purposes of the present invention isfrom 96 to 98% strength by weight sulfuric acid. Generally from 2 to 2.5parts by weight of concentrated sulfuric acid are used per part byweight of cyanopyridone VI.

The novel process is generally carried out by using concentratedsulfuric acid as initial charge and adding the cyanopyridone VI to it atroom temperature. The temperature will rise and is allowed to increaseto about 60°-70° C. This is followed by a period of stirring at thetemperature of the present invention. The reaction will generally endafter 5-8 hours, and the reaction mixture is then cooled down. It canthen be added to an ice-water mixture and be neutralized. The solutionthus obtained can be used directly for preparing the azo dyes of theformula I.

It can be of advantage to have small amounts of sulfur trioxide present,in which case the reaction medium is for example from 2 to 5% strengthby weight oleum.

The azo dyes of the formula I according to the present invention areadvantageously suitable for dyeing natural or synthetic substrates, forexample wool, leather or polyamide. The dyeings obtained have goodallround fastnesses.

The Examples which follow illustrate the invention.

EXAMPLE 1

163 g of the cyanopyridone of the formula ##STR11## were introduced intoa mixture of 40 g of oleum (24% strength by weight) and 380 g ofsulfuric acid (100% strength by weight). The temperature was allowed torise from 15° C. at the start of the addition to a maximum of 70° C. Themixture was stirred at from 70° to 80° C. for 2 h and then heated to 90°C. to split off CO₂. Then the reaction temperature was raised over about4 h to 130°-135° C. in such a way that the elimination of CO₂ could becontrolled. This was followed by stirring at from 130° to 135° C. for afurther 6 h.

The melt obtained on cooling was poured with stirring onto about 1000 gof ice and 500 ml of water, and the resulting precipitation was adjustedwith sodium hydroxide solution to pH 7 while cooling at <40° C. Theresult obtained was a clear solution (which can precipitate sodiumsulfate on standing) of the sulfopyridone of the formula ##STR12##

EXAMPLE 2

340 g of the cyanopyridone of the formula ##STR13## were introduced intoa mixture of 760 g of sulfuric acid (100% strength by weight) and 80 gof oleum (24% strength by weight) and reacted as described in Example 1.About 0.97 mol was obtained of the sulfopyridone of the formula##STR14## in the form of an aqueous solution.

EXAMPLE 3

30 g of 4-amino-4-methylbenzophenone hydrochloride were stirred up in 55ml of 17% strength by weight hydrochloric acid. The mixture was thencooled down to 0° C., about 40 g of ice and at the same time 20 ml of23% strength by weight aqueous sodium nitrite solution were added insuch a way that the temperature of the diazotization batch did not riseabove 10° C. The batch was subsequently stirred for a further 1 h whilebeing cooled down with ice to 0°-5° C. After excess nitrous acid wasdestroyed, the pH of the resulting diazonium salt solution was raisedwith a little sodium acetate and sodium hydroxide solution to 5-6 at <0°C. Then 14.85 g of the sulfopyridone of the formula ##STR15## were addedas an aqueous solution over 20 min while the pH was maintained withinthe range 4 to 7.5 by addition of sodium hydroxide solution.

The dye of the formula ##STR16## came down as a crystalline precipitateand was isolated at pH 7 in the form of the disodium salt by saltingout. Drying left 45 g of a yellow powder which gives a yellow solutionin water. Dyeing 100 g of retanned chrome cattlehide leather with 0.8 gof this dye by the conventional dyeing processes gives a strong lemonyellow surface dyeing with a bright hue.

Polycaprolactam fabric is dyed by conventional dyeing processes inbright, strong, lemon yellow shades, while wool is dyed in deep neutralyellow shades.

EXAMPLE 4

10 g of ethyl 4-aminobenzoate were diazotized by the method of Example3. Excess nitrous acid was destroyed, the pH of the diazonium saltsolution was raised with a little sodium acetate and sodium hydroxidesolution to 4.5-6.5 at 0° C., and then 14.85 g of the sulfopyridonementioned in Example 2 were added in the form of an aqueous solutionwhile the pH of the coupling batch was maintained within theabove-specified range. This yielded 25 g of the dye of the formula##STR17## Isolation at about pH 6.5 and drying were carried out asusual. The dye gives a yellow solution in water and dyes leather,polycaprolactam and wool in strong, lemon yellow to golden yellow hues.The dyeings have good light and wet fastnesses.

EXAMPLE 5

16.7 g of 4-aminoazobenzene-4-sulfonic acid were dissolved in 100 ml ofwater with sodium hydroxide solution at pH 8-9 and elevated temperature.Then 20 ml of 23% strength by weight aqueous sodium nitrite solutionwere added and the batch was allowed to cool down with stirring. Aftercooling with ice down to 0° C., the batch was acidified with 20 ml ofconcentrated hydrochloric acid. The suspension obtained was stirred atfrom 0° to 5° C. for 4 h. Then excess nitrous acid was destroyed, the pHof the suspension was raised with a little sodium acetate and sodiumhydroxide solution to 4.5-5.5, and an aqueous solution of 14.5 g of thesodium salt of the coupling component described in Example 1 was addedsimilarly to Example 4. Then the reaction mixture was adjusted withsodium hydroxide solution to pH 5.5. The resulting dye was precipitatedwith sodium chloride, and the precipitate was isolated and dried asusual to leave 31 g of a reddish orange powder of the formula ##STR18##which gives a golden yellow solution in water. The dye dyes wool,polycaprolactam and leather in a deep orange shade with good fastnessproperties.

The methods of Examples 1 to 5 also give the dyes described below inTables 1 and 2.

                                      TABLE 1                                     __________________________________________________________________________     ##STR19##                                                                    Ex.                               λ.sub.max [nm]                       No.                                                                              n D                     Hue    (in water)                                  __________________________________________________________________________     6 2                                                                                ##STR20##            lemon yellow                                                                         406                                          7 3                                                                                ##STR21##            lemon yellow                                        8 4                                                                                ##STR22##            lemon yellow                                        9 2                                                                                ##STR23##            lemon yellow                                                                         408                                         10 2                                                                                ##STR24##            lemon yellow                                       11 2                                                                                ##STR25##            lemon yellow                                       12 2                                                                                ##STR26##            lemon yellow                                       13 2                                                                                ##STR27##            lemon yellow                                       14 2                                                                                ##STR28##            lemon yellow                                       15 3                                                                                ##STR29##            lemon yellow                                       16 2                                                                                ##STR30##            lemon yellow                                       17 2                                                                                ##STR31##            lemon yellow                                       18 2                                                                                ##STR32##            lemon yellow                                       19 2                                                                                ##STR33##            greenish yellow                                    20 2                                                                                ##STR34##            neutral yellow                                     21 3                                                                                ##STR35##            neutral yellow                                     22 4                                                                                ##STR36##            neutral yellow                                     23 4                                                                                ##STR37##            neutral yellow                                     24 2                                                                                ##STR38##            neutral yellow                                     25 3                                                                                ##STR39##            neutral yellow                                     26 2                                                                                ##STR40##            greenish yellow                                    27 3                                                                                ##STR41##            greenish yellow                                    28 4                                                                                ##STR42##            greenish yellow                                    29 2                                                                                ##STR43##            greenish yellow                                    30 3                                                                                ##STR44##            greenish yellow                                    31 2                                                                                ##STR45##            greenish yellow                                    32 3                                                                                ##STR46##            greenish yellow                                    33 2                                                                                ##STR47##            greenish yellow                                    34 3                                                                                ##STR48##            greenish yellow                                    35 4                                                                                ##STR49##            greenish yellow                                    36 2                                                                                ##STR50##            greenish yellow                                    37 2                                                                                ##STR51##            greenish yellow                                    38 2                                                                                ##STR52##            neutral yellow                                     39 2                                                                                ##STR53##            neutral yellow                                     40 2                                                                                ##STR54##            greenish yellow                                    41 3                                                                                ##STR55##            greenish yellow                                    42 4                                                                                ##STR56##            greenish yellow                                    43 2                                                                                ##STR57##            orange                                             44 3                                                                                ##STR58##            orange                                             45 2                                                                                ##STR59##            orange                                             46 3                                                                                ##STR60##            orange                                             47 2                                                                                ##STR61##            orange                                             48 3                                                                                ##STR62##            orange                                             49 2                                                                                ##STR63##            orange                                             50 2                                                                                ##STR64##            orange                                             51 3                                                                                ##STR65##            orange                                             52 2                                                                                ##STR66##            orange                                             53 2                                                                                ##STR67##            orange                                             54 3                                                                                ##STR68##            orange                                             55 2                                                                                ##STR69##            neutral yellow                                     56 2                                                                                ##STR70##            orange                                             57 3                                                                                ##STR71##            orange                                             58 2                                                                                ##STR72##            orange                                             59 2                                                                                ##STR73##            greenish yellow                                    60 2                                                                                ##STR74##            neutral yellow                                     61 3                                                                                ##STR75##            neutral yellow                                     62 2                                                                                ##STR76##            neutral yellow                                     63 3                                                                                ##STR77##            neutral yellow                                     64 2                                                                                ##STR78##            neutral yellow                                     65 2                                                                                ##STR79##            greenish yellow                                    __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________     ##STR80##                                                                    Ex.                                                                           No.                                                                              D                     n W Y  Hue                                           __________________________________________________________________________    66                                                                                ##STR81##            1 --                                                                              CH.sub.3                                                                         greenish yellow                               67                                                                                ##STR82##            1 --                                                                              CH.sub.3                                                                         greenish yellow                               68                                                                                ##STR83##            1 --                                                                              CH.sub.3                                                                         greenish yellow                               69                                                                                ##STR84##            1 --                                                                              CH.sub.3                                                                         greenish yellow                               70                                                                                ##STR85##            1 --                                                                              CH.sub.3                                                                         greenish yellow                               71                                                                                ##STR86##            1 --                                                                              CH.sub.3                                                                         greenish yellow                               72                                                                                ##STR87##            1 --                                                                              CH.sub.3                                                                         greenish yellow                               73                                                                                ##STR88##            1 --                                                                              CH.sub.3                                                                         greenish yellow                               74                                                                                ##STR89##            1 --                                                                              CH.sub.3                                                                         greenish yellow                               75                                                                                ##STR90##            1 --                                                                              CH.sub.3                                                                         orange                                        76                                                                                ##STR91##            1 --                                                                              CH.sub.3                                                                         orange                                        77                                                                                ##STR92##            1 --                                                                              CH.sub.3                                                                         orange                                        78                                                                                ##STR93##            1 --                                                                              CH.sub.3                                                                         orange                                        79                                                                                ##STR94##            1 --                                                                              CH.sub.3                                                                         orange                                        80                                                                                ##STR95##            1 --                                                                              CH.sub.3                                                                         orange                                        81                                                                                ##STR96##            3 --                                                                              H  greenish yellow                               82                                                                                ##STR97##            4 O H  greenish yellow                               83                                                                                ##STR98##            3 --                                                                              H  greenish yellow                               84                                                                                ##STR99##            4 O H  greenish yellow                               85                                                                                ##STR100##           1 --                                                                              H  orange                                        __________________________________________________________________________

We claim:
 1. A sulfopyridone of the formula V ##STR101## where X is C₂-C₈ -alkylene with or without interruption by an ether oxygen atom, inthe form of the free acid or its salts.
 2. The sulfopyridone of claim 1,wherein X is C₂ -alkylene.
 3. The sulfopyridone of claim 1, wherein X isC₃ -alkylene.
 4. A process for preparing the sulfopyridone of claim 1,which comprises reacting a cyanopyridone of the formula VI ##STR102##where X is as defined in claim 1, with concentrated sulfuric acid atfrom 80° to 130° C.
 5. The process of claim 4, wherein the reaction iscarried out at from 90° to 125° C.
 6. The process of claim 4, wherein 2to 2.5 parts by weight of concentrated sulfuric acid are used per partby weight of cyanopyridone (VI).
 7. The process of claim 4, wherein theconcentrated sulfuric acid contains sulfur trioxide in amounts to yield2 to 5% strength by weight oleum.